sphincter

[sfingk-ter] /ˈsfɪŋk tər/
noun, Anatomy
1.
a circular band of voluntary or involuntary muscle that encircles an orifice of the body or one of its hollow organs.
Origin
1570-80; < Late Latin < Greek sphinktḗr, equivalent to sphing-, base of sphíngein to hold tight + -tēr suffix denoting agent
Related forms
sphincteral, sphincterial
[sfingk-teer-ee-uh l] /sfɪŋkˈtɪər i əl/ (Show IPA), sphincteric
[sfingk-ter-ik] /sfɪŋkˈtɛr ɪk/ (Show IPA), sphincterate
[sfingk-ter-it, -tuh-reyt] /ˈsfɪŋk tər ɪt, -təˌreɪt/ (Show IPA), adjective
British Dictionary definitions for sphincter

sphincter

/ˈsfɪŋktə/
noun
1.
(anatomy) a ring of muscle surrounding the opening of a hollow organ or body and contracting to close it
Derived Forms
sphincteral, adjective
Word Origin
C16: from Late Latin, from Greek sphinkter, from sphingein to grip tightly
Word Origin and History for sphincter
n.

1570s, from Middle French sphincter, from Late Latin sphincter "contractile muscle," from Greek sphinkter "band, anything that binds tight," from sphingein "to squeeze, bind," of unknown origin. First used in anatomical sense by Galen.

sphincter in Medicine

sphincter sphinc·ter (sfĭngk'tər)
n.
A ringlike muscle that normally maintains constriction of a body passage or orifice and that relaxes as required by normal physiological functioning. Also called anatomical sphincter.

sphinc'ter·al or sphinc·ter'ic (-těr'ĭk) adj.
sphincter in Science
sphincter
  (sfĭngk'tər)   
A ring-shaped muscle that encircles an opening or passage in the body. The opening and closing of the anus is controlled by contraction and relaxation of a sphincter, as is the opening that leads to the stomach from the esophagus.